Out of display devices, a liquid crystal display has advantages of a small size, a thin volume and low power consumption. Accordingly, such a liquid crystal display has been used for a notebook computer, an office automation device, an audio/video device and so on. Especially, an active matrix liquid crystal display including a thin film transistor (hereinafter, TFT) as a switch device is proper to display a dynamic image.
Brightness and contrast output from a plurality of pixels of the liquid crystal display are set differently for each product and each manufacturer and even the same image output from the liquid crystal display can be realized with a different color sense.
It is necessary to adjust a color sense of a screen in case a user is doing a work of which a color sense realized on a screen is important. In a video wall including a plurality of liquid crystal displays matrix-arranged to realize one screen, the color sense of one liquid crystal display might be different from that of the neighboring liquid crystal display and such a difference of the color senses might deteriorate the unity of the screen. Accordingly, it is necessary to calibrate the difference of the color senses.
A conventional calibrator is in contact with a screen of a display device, with a cable hung on a top of the display device. To use such a method of the conventional calibrator in a large video wall, a long cable has to be used. If the cable is long, it is inconvenient to move the position of the calibrator.